Is that thing in the upper-right corner supposed to be so tarnished-looking? Did it overheat? Exposed to corrosive gas?

Actually, it's the only part I'll reuse. It's a Freescale MPX5700 pressure sensor. It's encapsulated in black plastic so it looks bad in the photo. (I should re-phrase... I'll test them and if they're OK, I'll reuse them.)

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I wonder how the 7805 in the middle was damaged. And aren't they supposed to each have two capacitors?

That would have been wise... The "damage" is intentional, though! As built, there was not quite enough room for the #4 bolt holding the Uno to the other side. Nothing a hacksaw wouldn't fix.

The whole project is a scrum meter for a rugby club. They want to see how various combinations of players put pressure on their opponents. They practice against padded scrum stands that have air cylinders supporting them. The MPX5700's measure the air pressure and I'll use the result to show the peak pressure, and graph the pressure over time on a Processing display.

However it turns out, I'm certain it'll be a thousand percent better than what they had.

BTW, CB, thanks for your first feedback. I was pretty sure there wasn't any way of getting any meaningful code off the original Uno's. But you never know who's got a miracle solution in their back pocket.